Study on the durability of steel wire under the coupling effects of harsh environment and variable loads

Abstract

steel wire is regarded as the most important component of cable-stayed bridges, and it has been widely used in practical engineering. Most of the studies only considered the effect of variable loads and chloride corrosion on the durability of steel wires separately. However, few studies have reported their coupling effects. In order to investigate the durability of steel wires considering their coupling effects, A physical test was performed to investigate the corrosion–fatigue performance. After the experiment finished, a tensile device was used to test the mechanical properties of corroded steel wires with different corrosion degrees. Then the corrosion characteristics of different specimens and fracture surface morphology of the steel wires were investigated using a 3D scanner, which was used to analyse the failure mode of each type of steel wires. In addition, a model was proposed to evaluate the reliability of corroded steel wires. Finally, a fatigue test was conducted to explore their fatigue performance and the S-N curve of steel wires with different corrosion degrees was obtained. The results show that the fatigue life of the steel wires is mainly affected by environmental effects when the steel wire at low stress amplitudes. However, as the stress amplitude increases, the fatigue life of it is decided by the stress amplitude. The fracture morphology of the corroded steel wires can be two categories: single-source fracture and multi-source fracture, For the steel wires corroded slightly, cracks often drive from one fatigue source (pit defect). As the corrosion degrees increase, the depth of pits enhances, cracks drive from different fatigue sources. In addition, the propagation zones decrease, and the rupture regions increase, as the steel wires corroded seriously.